public class Demo1 {
    public static void main(String[] args) throws InterruptedException {
        Thread t = new Thread(() -> {
            for(int i = 0; i < 30; i++) {
                System.out.println("hello thread");
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    throw new RuntimeException(e);
                }
            }
        });

        System.out.println(t.isAlive());  //false

        t.setDaemon(true);
        t.start();
        System.out.println(t.isAlive());  //true

        //Thread.sleep(5000);

        for (int i = 0; i < 2; i++) {
            System.out.println("hello main");
            Thread.sleep(1000);
        }
        System.out.println(t.isAlive());  //false
    }
}
